To satisfy demands for wireless data traffic having increased since commercialization of 4th-Generation (4G) communication systems, efforts have been made to develop improved 5th-Generation (5G) communication systems or pre-5G communication systems. For this reason, the 5G communication system or the pre-5G communication system is also called a beyond-4G-network communication system or a post-Long Term Evolution (LTE) system.
To achieve a high data rate, implementation of the 5G communication system in an ultra-high frequency (mmWave) band (e.g., a 60 GHz band) is under consideration. In the 5G communication system, beamforming, massive multi-input multi-output (MIMO), full dimensional MIMO (FD-MIMO), an array antenna, analog beamforming, and large-scale antenna technologies have been discussed to alleviate a propagation path loss and to increase a propagation distance in the ultra-high frequency band.
For system network improvement, in the 5G communication system, techniques such as an evolved small cell, an advanced small cell, a cloud radio access network (RAN), an ultra-dense network, a device to device (D2D) communication, a wireless backhaul, a moving network, cooperative communication, coordinated multi-points (CoMPs), and interference cancellation have been developed.
In the 5G system, advanced coding modulation (ACM) schemes including hybrid frequency-shift keying (FSK) and quadrature amplitude modulation (QAM) modulation (FQAM) and sliding window superposition coding (SWSC), and advanced access schemes including filter bank multi carrier (FBMC), non-orthogonal multiple access (NOMA), and sparse code multiple access (SCMA) have been developed.
Current wireless communication systems are evolving to high-speed, high-quality wireless packet data communication systems to provide data services and multimedia services beyond the initial versions that have provided voice-centered services. To this end, various standardization organizations, such as the 3rd-Generation Partnership Project (3GPP), the 3GPP2, and the Institute of Electrical and Electronics Engineers (IEEE), are preparing 3G evolution mobile communication system standards employing multiple access schemes using multi-carriers. Recently, various mobile communication standards, including Long Term Evolution (LTE) of the 3GPP, Ultra Mobile Broadband (UMB) of the 3GPP2, and 802.16m of the IEEE, have been developed in order to support a high speed-high quality wireless packet data transmission service based on a multiple access scheme using a multi-carrier.
Existing 4G evolution mobile communication systems, such as LTE, UMB, and 802.16m, are based on multi-carrier multiple access schemes, employ multiple input multiple output (MIMO) schemes to improve transmission efficiency, and use various technologies, such as beamforming, adaptive modulation and coding (AMC), channel sensitive scheduling, and the like. The aforementioned techniques increase system capacity performance through transmission efficiency improvement achieved by collecting transmission power from various antennas depending on channel quality, etc., adjusting the amount of transmission data, selectively transmitting data to a user having good channel quality, and so forth. Because of mostly operating based on channel state or status information between an evolved NodeB (eNB) (or a base station (BS)) and a user equipment (UE) (or a mobile station (MS)), these schemes need to measure a channel state or status between the eNB and the UE, and for this end, a channel status indication reference signal (CSI-RS) is used. The eNB means a downlink transmission and uplink reception apparatus located in a predetermined place, and one eNB performs transmission and reception with respect to a plurality of cells. In a wireless communication system are geographically distributed a plurality of eNBs, each of which performs transmission and reception with respect to a plurality of cells.
The existing 4G wireless communication systems such as LTE/LTE-A use the MIMO technique that performs transmission using a plurality of transmission and reception antennas to expand a data rate and a system capacity. The MIMO technique performs transmission by spatially dividing a plurality of information streams using a plurality of transmission and reception antennas. As such, transmission based on spatial division of the plurality of information streams is referred to as spatial multiplexing. Generally, the number of information streams to which spatial multiplexing is applicable depends on the number of antennas of each of a transmitter and a receiver. The number of information streams to which spatial multiplexing is applicable is defined as a rank of transmission. For MIMO techniques supported by standards up to LTE/LTE-A Release 11, spatial multiplexing is supported for 8 transmission/reception antennas and a maximum of 8 ranks are supported.
The recent 4G evolution wireless communication system standards such as the 3GPP LTE(-A) or the IEEE 802.16m mostly employ multiple access schemes using multiple subcarriers such as orthogonal full dimension (FD) multiplexing (multiple access) (OFMD(A)) as multiple access schemes. Spatial multiplexing that improves frequency efficiency by using MIMO that performs transmission and reception using multiple antennas, together with a multiple access scheme based on multiple subcarriers, is used for wireless communication. In a wireless communication system supporting multiple antennas, efficient transmission power control is one of important technical issues.